Cut the lobster meat in large (3/4-inch) dice. Heat 3 tablespoons of the butter in a medium (10-inch) saute pan over medium-high heat. Add the lobster, celery, 1 teaspoon salt, and 1/2 teaspoon pepper and cook, stirring occasionally, for 2 to 3 minutes, until just heated through. Off the heat, sprinkle the lobster with the dill, parsley, and half of the lemon juice. Stir well.
Meanwhile, heat the remaining 2 tablespoons of butter in a large (12-inch) saute pan, until the butter sizzles. Place the rolls in the pan on their sides (you are toasting the outsides, not the insides) and cook over medium-high heat for 2 minutes on each side, until nicely browned.
Place the rolls, cut side up, on a platter. Divide the lobster mixture among the 6 rolls and sprinkle with extra dill, salt, and the remaining lemon juice. Serve hot while the rolls are crisp on the outside and the lobster filling is hot.