When a version controlled file is renamed in Explorer, why can't you offer to rename in Subversion as well?
Firstly, we cannot access the explorer rename command as it is not part of the TortoiseSVN shell extension.
Secondly, even if we could find a way around that limitation, it would not be desirable. There are occasions when you want to rename only in explorer. Here are 2 examples:
TortoiseSVN 1.5.0 will have the ability to 'repair' a move/rename which was done without using the Subversion commands. Repairing works by selecting two files where one is unversioned and the other missing, then choose "repair move" from the context menu.