Commenting on Ellis's arrival, Lam said: "It's great to have Dave here with us now. This week, he's been observing training and our systems and really getting to know the guys.
"I've worked with Dave in New Zealand and he is a truly innovative technical coach who gets results.
"A huge part of our vision here at Connacht Rugby is having a rugby programme that develops players so that they can perform the basic skills under pressure and against any team they face. I'm thrilled that Dave has come in to head up that skills programme for us."
Ellis added: "I'm delighted to finally be here and I'm really looking forward to getting stuck into the job at hand.
"It's clear that there is a lot of hard work being done behind the scenes here by a great group of people and I'm excited to be a part of that."