Preheat the oven to 400°F. Hold an asparagus spear at both ends and bend the bottom until the tough, woody section snaps (it will naturally snap off where the tough part of the vegetable ends and the tender part begins). Using that spear as a guide, use a knife to remove the bottoms of the rest of the bunch. Place the asparagus in a baking dish. Drizzle with the olive oil, sprinkle with the Parmesan, and season with salt and pepper; toss to coat. Roast until just tender, 10 to 12 minutes. Sprinkle the lemon juice over the asparagus.