How to pickle split window?

[Haines Brown]

I normally run emacs with split windows and so have 

   (split-window-horizontally)

in its initialization file. However, I periodically interrupt work
to run M-x gnus. When I close gnus, I am not returned to a split window,
but to a single window. 

What can I do to return to the split window that displays my prior state
automatically after closing gnus without having to do an emacs reload
command with:

  ;; Enable M-x reload
  (defun reload () "Reloads .emacs interactively."
    (interactive)
    (load "~/.emacs"))

Haines Brown