Only in the most dire of "gotta go right now" circumstances would I not preheat my engine. I like to see at least 50F oil temperature before I start in the winter.
In Canada you are well organised enough to be able to do this; with the weather so cold in a "normal" Canadian winter it's good to see a country that gears itself up to deal with whatever nature throws at you all. I wish that the UK was so prepared.
I understand that in Canada it is not unusual for cars to be "plugged in" at night to enable electric heaters to keep their engines at a sensible temperature.