Capitalisation of company names starting with a lower case letter?

[IShallWearMidnight]

I'm proofreading some stuff at the moment, and this has me confused. If a sentence starts with "eBay" or "iTunes", do you capitalise the first letter? It looks wrong not to, but very strange to have "EBay". What do you reckon?

It is a trademarked name, so should be spelt / written as iTunes etc.

That is my opinion though, not an actual fact.

I think you leave it small (ie go back and undo computer's automatic capitalisation).

Guardian Style agrees.

thanks, that's what I've done, even though it makes me twitch

It would make me twitch too if it's at the start of a sentence. But I would follow the advice above after coming on here, as you did!.