In a small saucepan over medium-low heat, warm the garlic and butter until the butter melts. Set aside about 2 tablespoons for brushing on the buns.
Prepare the grill for direct cooking over medium heat (350° to 450°F).
Carefully cut the lobster tails in half lengthwise. Season the meat with a little salt and brush some of the garlic butter over the surface of each one. Brush the cooking grates clean. Grill the tails, meat side down, over direct medium heat, with the lid open, until the meat is opaque, 2 to 3 minutes. Turn the tails over, brush with more garlic butter, and continue to grill until the meat is slightly firm, about 3 minutes. Set aside to cool.
In a large bowl combine the mayonnaise, tomato, scallion, and lemon juice. Season with salt and hot sauce. Remove the lobster meat from the shells and cut into ½-inch pieces. Add the lobster meat to the mayonnaise mixture. For best flavor, chill at least 1 hour. Mix in the chervil just before serving.
Using a serrated knife, trim some of the crust from the sides of the buns. Brush the remaining garlic butter on the cut sides (outside only) of the buns and toast over direct medium heat until golden brown on both sides, about 1 minute, turning once.
Place ⅓ cup romaine on the bottom of each roll and then top with the lobster mixture.