Unfortunately, you can only display the 3-month calendar with the built-in
However, a work-around that I use is to enable line truncation so that the extra months flow out of sight across the screen rather than wrap into the next line.
You can add the following to your init file to get that effect:
(defun my-calendar-hook ()
"Turn line truncation on."
(add-hook 'calendar-mode-hook #'my-calendar-hook)
If you would like the current month to be on the left, you can instruct Emacs to scroll one month over when it opens the initial window. The function in question is
To get it to run automatically, you need to add it to the relevant hook, so put the following in your init file:
(add-hook 'calendar-initial-window-hook #'calendar-scroll-left)