If you want to capture everything no matter what the string might be after =
then you could use:
(wysija-page=\d+)(?:.*)(controller=\w+)(?:.*)(action=\w+)
example: http://regex101.com/r/tP1fG3
If you specifically only want page=1 controller=confirm, etc.
(wysija-page=1)(?:&.*)(controller=confirm)(?:.*)(action=subscribe)
example: http://regex101.com/r/hI3pO2