Cook the pasta according to the package directions, reserving ½ cup of the cooking water. Transfer the pasta to a large bowl.
Meanwhile, heat the oil in a skillet over medium heat. Add the leeks and cook until soft but not browned, stirring frequently, about 5 minutes. Remove the leeks; set aside.
Add the artichokes to the skillet and cook for about 3 minutes per side.
Return the leeks to the skillet and toss with the artichokes. Stir in the lemon juice, 3 teaspoons salt, and 1 teaspoon pepper.
Add the vegetables to the pasta and toss with half the Parmesan. Add some reserved cooking water to moisten, if necessary.
Sprinkle with the remaining cheese.