ISPs don't generally log the sites you visit unless LE specifically requests it. If LE is watching your internet connection, you're probably fucked anyway. The purpose of Tor is to prevent them from identifying you. You're thinking about this from your perspective, "I'm using Tor and somebody can see that." You have to think about it from their perspective, "Somebody is blogging, where the fuck are they?" If you use Tor correctly and don't reveal info about yourself, they will never be in a position to watch your internet connection, because they won't know where to look.