Saving everyone else time is not really a concern, since now that Laharl has left the group (or rather, they've left him behind) he and Flonne are on their own. Laharl would have to get her up to speed on events that he probably doesn't fully understand himself and then suddenly go through all the character development you have planned for him thanks to Flonne in order to join them, so he's got plenty of time. Once the two reunite, they probably ought to descend back down to Tostarena Town or something. I can put a little something for Flonne in my update tomorrow for you.