In medium size bowl toss the shredded cheese with the cornstarch. In medium size saucepan, heat the broth, lemon juice, garlic, oregano and cumin until barely simmering. Add the cheese, a handful at a time, stirring until the cheese is melted before adding more. When all the cheese has been added, stir in the scallions and olives. Transfer fondue to a fondue pot and keep warm over a fondue burner. Serve with vegetables or bread for dipping.