Sounds kind of old, but I think it could make a come back. It honestly isn't that bad, though his friends might joke with nick names like Thursday and Thirsty.
This is a really cool name, but I like it much better spelled Thurston. I'm aware of the fact that the name is old-fashioned, and it does sound like 'thirst' and 'thirsty', which is why I'd rather use the name Thorston as the middle name of my son, if I ever have kids, that is.