1. Toss Le Gruyère and cornstarch together and set aside. Bring wine to a boil in a large saucepan over medium-high heat. Stir in cheese and cornstarch mixture. Lower heat to medium-low and cook, stirring constantly in a figure-8 or zigzag motion, until cheese is melted and the mixture thickens slightly, 5 to 10 minutes.
2. Place a fondue pot in the middle of the table. Pour cheese mixture into the pot and place over a gentle heat source. Arrange bread, potatoes and apples on a platter and serve with the fondue for dipping.