Charles Masson and Christian Delouvrier are gearing up for a September opening of their new restaurant in the old Post House space at the Lowell Hotel. It will be called Majorelle, after the French painter Jacques Majorelle, who spent much of his time painting in Morocco. "I was retiring, but Charles called me, so I am working on a menu right now,'' says the famed chef, who earned four stars from the New York Times at Lespinasse before working for David Bouley and then becoming executive chef at La Mangeoire. "It's French but there will definitely be Mediterranean touches,'' notes Masson, who will be the restaurant's manager. "We are opening up the back garden which has made a huge difference. It's much lighter than the Post House."