In a small bowl, toss the cheeses with cornstarch and set aside.
Rub the inside of a ceramic fondue pot with the garlic clove, then discard. Store the fondue pot in a 250°F oven until ready to use.
Bring the wine and lemon juice to a gentle simmer in a medium saucepan over medium heat. Gradually stir the cheese into the simmering liquid. Melting the cheese gradually encourages a smooth fondue. Once smooth, stir in the kirsch, dry mustard, and nutmeg.
Using oven mitts, carefully remove the fondue pot from the oven and pour in the warm fondue.
Arrange the dippers around the fondue pot, spear with fondue forks, dip, and enjoy!