Allowing spaces in the regexp for outlines

[Heime]

Have made a regexp for outlines to use ';;;' followed by 'H' and a number.

I would like to allow any number of spaces between the ';;;' and the letter 'H'.
How can I change the regexp to allow such a capability ?

(defvar el-hglevels
  '( (";;; H1" . 1) (";;; H2" . 2) (";;; H3" . 3) (";;; H4" . 4) )
  "Outline levels for elisp major mode.")

(defun outlhg-regexp ()

  (cond

    ((memq major-mode '(emacs-lisp-mode lisp-interaction-mode))
       (let ( (hglevels el-hglevels) )
         (setq outline-regexp
               (concat (regexp-opt (mapcar 'car hglevels)) "\\>"))
         (setq outline-heading-alist hglevels)
         (setq-local outline-level 'outline-level))) ))