My Kryptonite lock did the same 90-degree thing due to dirt, not freezing. Torque will not help. Basically a bit of mechanism that ought to be sliding somewhere, isn't, because it has something stuck to it. I fixed this problem by flushing the keyhole out with about half a can of WD-40 and trying it 500 times. It was a serious pain in the ass. In your case it's probably ice---try heating the key with a lighter, using lock de-icer or submerging the whole thing in a bucket of hot water. Persistence will probably pay off.

Also I noticed that my lock is more cooperative when the key hole is facing downward, and a "bump" seemed to help---knock the lock a bunch against the bike rack.