McGrath, I just remembered that I never got back to you on this tread. Sorry.
A link for L'Arche Canada is www.larchecanada.org If you click on "Contact us", you will be offered lists of L'Arche communities, with their websites if they have them.
In a vision meeting our leader talked a bit about terminology. She said the the most important things were to resist the temptation to call adults boys and girls, and whichever term you use to describe the disability, you should put the person first (i.e. a man with a mental handicap, not a mentally handicapped man).