[xmonad] Is it possible to reset Xmobar without restarting Xmonad?

[Leo Alekseyev]

I am using xmonad on a tablet PC where I sometimes change the screen
orientation.  Unfortunately, Xmobar doesn't properly rescale itself
when the screen goes from portrait to landscape.  If I kill it and
then restart, the new Xmobar instance doesn't communicate with the
Xmonad LogHook anymore.  The only solution for me right now is
restarting Xmonad, which is suboptimal because
(1) config takes noticeable time to compile and
(2) my workspace / window configuration gets completely fubared on
every Xmonad restart (e.g. all the terminal windows like to move
themselves to a single workspace even though there isn't a doShift
directive to do so in the config (it might have something to do with
my using compositing).

If anyone has advice on how to reset Xmobar without Xmonad restart (or
at least how to make the Xmonad restart not touch my window config),
I'd love to hear it!

--Leo