Just noticed this thread, apologies if this reply’s too late to be useful.

I took my Canon 1000D to Lapland last March (Abisko in Sweden), perhaps a bit warmer than this time of year (typically around -12 oC but down to -19 during the day) and had no problems at all photographing out in the snow and the Northern lights. The lens would steam up as soon as I came inside, but outside there were no problems at all.

The Sony mini DV video camera was a different story, but it seems to work after a thorough defrosting.

Have fun, it’s lovely.