In a large saucepan, heat the olive oil. Add the onion and cook over moderately high heat, stirring, until softened, about 2 minutes. Add the rice and cook, stirring until opaque, about 3 minutes. Add the white wine and cook, stirring, until completely absorbed, about 1 minute. Add 1 cup of the warm stock and cook over moderate heat, stirring, until nearly absorbed. Continue adding the stock 1 cup at a time and stirring until it is absorbed between additions. After about half of the stock has been added, stir in the corn, then add the remaining stock. The rice is done when it's al dente and creamy, about 25 minutes total. Stir in the cheese and butter; season with salt and pepper. Discard the bay leaf and serve.