As much as I would like to say otherwise, I'd have to side with the company. It is the responsibility of the employee to arrive for work by the appointed time, not the company. If you choose to bike, that is great, but ultimately your choice. It has advantages, but disadvantages as well. Yet, the company couldn't care less, so long as you are on time. Others choose to drive and that has advantages and disadvantages. Again, the company doesn't care how you get to work, only that you DO get to work. It sounds as if they have been accomodating already, but agreeing to allow you not to come in when everyone else was able to is asking too much.

I live in Canada as well (though in Toronto where it is usually alot more mild) and I commute regularly as well. However, when the temps get to be like they are today (-31---a rare occurence), I take public transit. It's my responsibility to be here, even though I have a better computer at home and could easily do my job from there perhaps even more productively.