My personal oppinion: There can't be a workaround if the windows updater tryes to run explorer shell extensions, update, change it's files etc. The only one who could do anything about this is Microsoft, make their updating system so that the shell can be updated without it running.

Although technicaly it's fairly possible if your a cracker and know how to "manipulate" any windows update installers so they bypass or alternatively run installations. But this wouldn't by far be as simple as just switching back to explorer for a few minutes to update(unless you have winXP ofcourse, heard they had some pretty big updates).

I'd love to help if i could but my word of advice, simplify quickly switching between explorer and LS instead, it's a lot easier and you get used to it.