Try www.rhodondendron.org - click on 'plant care' then 'plant protection'.
They're an American site so more likely to understand your climate conditions.

Rhods are usually tough as old boots!
I had a favourite old rhod that spend 6 months (oct-march) dumped in a bucket as I was between houses. I never even thought to pot it properly and protect it from the cold. We had a horrendous, cold winter and as soon as it was planted in April it flowered beautifully!
Maybe keep an eye on the weight of snow that's on it, in case you break any branches.

I think that Lucklu's main issue will be with the amont of snow that they get in Ontario. On another site I have seen pictures of a members garden over the last three winters with snow up to the eaves. I don't know how you would protect any shrub from all that weight.