Two players who played with and against Elsom last season, Donncha O'Callaghan and Brian O'Driscoll, gave their views to us on the Wallabies' drum-playing talisman.
"I played against him before, he seems soft alright! Ah no, that's one thing you couldn't call that man," O'Callaghan told IrishRugby.ie.
"I think last season's performance for Leinster sums him up, the way he leads from the front. I think Australia have seen that now as well and placed him as captain.
"He's a huge momentum builder for them really, the way he carries the ball and the way he gives everything every time he goes out and plays.
"I'm not surprised that he's captain now. I wouldn't believe any of those Leinster lads that are calling him soft," he joked.
Having shared a dressing room with Elsom for much of last season, Ireland captain O'Driscoll knows more than most about what makes the Melbourne-born flanker tick.
"Rocky's a fantastic player, he was great for Leinster last season. I happened to bump into him in a restaurant in Dublin on Monday, we just chatted away for a while," he explained.
"But for 80 minutes on Sunday we'll put all that aside and we'll take each other on.
"We know a fair bit about him and his excellent ball-carrying skills. He's a smart footballer, he's a kind of a quiet leader...just going about his business.
"He's a world class player. I'm sure his mind will be solely focused on winning a Test match, as mine will.
"Certainly if you can keep him quiet, you're making life a lot easier for yourself."
This will be Elsom's fourth Test against Ireland. He was at number 8 for the Wallabies' 37-15 victory over Ireland in Perth in June 2006 and on the blindside for the 18-12 win in his native Melbourne in June 2008.
He also wore the number 6 jersey in the 21-6 defeat to Ireland when the Australians were last in Dublin in November 2006.
Ref Talk Radio: Don't forget to pick up your official HP Ref Talk Radio inside Croke Park on Saturday. Ref Talk Radio is only available inside the ground and will keep you up to date with all the action on the pitch.
Ref Talk Radio costs 10 Euro and is available from sellers inside Croke Park only.
FLANNERY BACKS CRONIN FOR HOOKER SPOT - BUT NOT JUST YET: Having recovered from a calf injury, Jerry Flannery will take his place as the starting hooker in the Ireland team for Sunday's GUINNESS Series clash with Australia at Croke Park.
Flannery began last season with Ulster's Rory Best breathing down his neck but he managed to hold onto the number 2 jersey for the guts of such a memorable season, starting twice in the autumn internationals and making four starts in the Grand Slam-winning campaign.
With Best currently out injured, Connacht youngster Sean Cronin has taken his chance to move to the next level and this Sunday will see him take his place on the Irish bench for the third successive international.
The 23-year-old was an unused replacement for Ireland's two-match tour of north America in the summer and will be itching to make his Test debut at Croke Park.
Flannery got an early glimpse of Cronin's potential when he was in the Munster Academy and feels he is destined to make his mark on the international stage.
"Sean is a very exciting player. He's come through a lot of the lines that I came through," said Flannery.
"He played his schools rugby in Limerick, played with Shannon and he's moved up to Connacht to try and get more game-time.
"He's been progressing well as a player, obviously I don't want to talk him up too much because he's trying to take my job.
"I'd say give him another six or seven years and he might be in there," he added with a wry smile.
Since the Grand Slam win, Flannery has had a very poor run of luck with injuries. He finished last season with both arms bandaged and his Lions dreams in tatters, and two calf injuries have prevented him from hitting the ground running with Munster this season.
He proved his fitness in recent days with the Irish squad, leading Declan Kidney to name him in the starting line-up to face the Wallabies in only his second game in five weeks.
Asked about his recovery from the latest calf injury, Flannery said: "It's good. I trained towards the latter end of last week, put in a few sessions this week and did a bit of fitness (on Wednesday) and it stood up fairly well.
"It looks like I've been out for six months, but by the time Munster started their pre-season at the start of July, I was back fully fit training.
"It was just towards the end of August when Munster had their first pre-season game, that I tore my right calf. I was out for six weeks with that.
"And then I came back, I played for Shannon and then came on against Leinster at the RDS and then played the full game against Northampton. I felt perfect. But then the following Tuesday, I tore my left calf.
"I don't think there was anything I could have done differently, we've analysed it and it was just some bad luck," admitted the 31-year-old.
RANKINGS COULD SEE PLENTY OF CHANGES: With all bar one of world rugby's top 20 sides in action this weekend - be it in Europe or the Rugby World Cup qualifiers in Africa and the Americas - there is plenty of scope for changes in the IRB World Rankings.
Not that it will be a concern for Ireland coach Declan Kidney. Twelve months ago, the rankings situation was vital as Kidney's charges beat Argentina to seal their top eight ranking and a second seed position in the draw for the 2011 Rugby World Cup.
This time around, the rankings matter little - although it would be nice to see Ireland, as Grand Slam champions, maintain their current position in fourth place as the northern Hemisphere's top-ranked side.
Even better would be a place in the top three but Australia, who are hoping to beat all four home Unions and repeat their own 1984 Grand Slam tour success, will not give up their third-placed ranking without a fight.
As things stand, Ireland will need to beat the Wallabies by more than 15 points - something they have never done before in 27 meetings - to take over in third in Monday's updated rankings.
Notably, Ireland's own position as the leading European nation in the rankings could also be under threat as defeat against Australia - a first loss in 2009 - and a French victory over South Africa would see Les Bleus take over that mantle and fourth spot.
Kidney's men could actually slide to sixth if Argentina make it two wins in-a-row against eighth-ranked England by triumphing at Twickenham on Saturday. Sixth-ranked Argentina can actually return to fourth if they beat England and France and Ireland both lose.
"This is ten days' growth, people might be a little bit worried about it! I did handlebars last year and this year I'm trying to grow something...I might have to dye it because it's not exactly too prominent!
"It's all to raise awareness for men's health, testicular and prostate cancer. Last year was the first year it was in Ireland. I've hopefully recruited some of my friends and there's one or two players doing it as well. We're trying to bring the 'mo' back for Movember!"
- Ireland number 8 Jamie Heaslip tells Irish Rugby TV about his newly sprouted moustache which he is growing for the 'Movember' campaign this month
"I remember not being too nervous before it, just really looking forward to it. I was playing against Australia as well, over in Brisbane. The nerves came on when the fireworks went off when they came out of the pitch - I wasn't expecting that!
"Once the whisle went for the start of the game, all those nerves evaporated and you just get on with what you're comfortable with and that's playing."
- Ireland captain Brian O'Driscoll reflects on his first Test cap which ironically came against Australia back in June 1999. Sunday's game will be his 100th Test for Ireland and the Lions
"I don't know whether he was smiling or not, but George is very professional on that side of things.
"He certainly always thinks about the team first. That's first and foremost in his mind, he never veers away from that.
"He'll obviously just be thinking about what my contribution to the team is and make sure that's on the training pitch as well as during the game."
- Australia forwards coach Jim Williams talks about flanker George Smith who has been dropped to the replacements bench for Sunday's game. David Pocock will start in his place
5 - A total of five players made their Test debuts for Ireland and Australia when the sides met at Ballymore Stadium in Brisbane in June 1999. Brian O'Driscoll, Matt Mostyn and Tom Tierney made their bows for the tourists, while Jim Williams and Nathan Spooner gained their first caps for Australia.
Of course, 'Seamus' went on to make his mark with Munster as a player and coach and Spooner played with O'Driscoll at Leinster between 2001 and 2003
11 - The Wallabies have played eleven Test matches in the five months since Ireland's last international match (the 27-10 Setanta Challenge Cup win over the USA).
Most of those games were, of course, in the Tri Nations tournament, in which Robbie Deans' men finished bottom of the table. But they managed to get back to winning ways last Saturday against England
2 - When Australia last visited Dublin back in November 2006, they only scored two penalty goals through captain Stirling Mortlock in a 21-6 defeat.
They also suffered two sin-binnings on a forgettable afternoon for them at Lansdowne Road, with both flanker Phil Waugh and replacement Mat Rogers seeing yellow