You can also force the lone king to a corner by placing the queen a knights move away from the King - forcing the king to move back. Keep repeating this until the lone king is in the corner with just two squares to rattle around on. Now you can march your king over to protect the queen while she delivers mate. Beware the stalemate.
By a knights move away I mean that you place the queen so that if it were a knight the king would be in check. This way the queen is safe from capture and the king is forced to move back. He can wriggle a bit but eventually be gets to the side from where the knights move technique forces him to move toward a corner.