Place a pizza stone on the floor or the lowest rack of your oven. Preheat the oven to 500 degrees F.
Pat the pizza dough into a 12-inch diameter circle and place it on a peel. Spread on the heavy cream, then the mozzarella. Place the ham slices on evenly and scatter the onions over the top. Sprinkle the lemon juice over everything. Slide onto the stone and bake for 8 to 10 minutes. Cover the pizza with the baby arugula and grind on some black pepper.