Place the oil in a bowl and squeeze in a wedge or two of lemon. Using the rosemary as a basting brush, lightly brush the ribs on both sides with some of the lemon oil. Generously season the ribs on both sides with salt and pepper, then the herbes de Provence. You can grill the ribs right away, but they’ll be even more flavorful if you let them marinate for 15 to 20 minutes.
When ready to cook, attach the spit to the rotisserie mechanism and turn on the motor. Grill the ribs, covered, until golden brown and cooked through, 40 minutes to 1 hour, depending on their size. Baste the ribs with lemon oil as they cook, using the rosemary as a brush. The ribs are done when the meat has shrunk back about ¼inch from the ends of the bones. Serve at once.