Preheat the oven to 400 degrees F (200 degrees C).
In a large bowl, stir together the sugar, cinnamon and cornstarch. Add blueberries and lemon juice, and stir gently to coat berries. Pour into the pie crust.
Bake for 30 minutes in the preheated oven. When the pie is done, whip the egg whites in a large glass or metal bowl until soft peaks form. Gradually sprinkle in sugar while continuing to whip into a stiff meringue. Spread over the hot filling so that the meringue is sealed to the crust all around.
Bake for 10 more minutes, or until meringue is nicely browned. Cool to room temperature before refrigerating or serving.