Bring a large pot of water to a boil and add 1 tablespoon of salt and some olive oil. Add the pasta and cook it for 8 to 10 minutes, until al dente. Add the corn to the pasta and cook it for another 2 minutes, until the corn is tender. Drain the pasta and corn together in a colander and pour them into a large mixing bowl. Add the scallions, diced pepper, tomatoes and lobster, tossing gently to combine. Allow to cool slightly.
In a small bowl, whisk together the mayonnaise, sour cream, lemon juice, 2 teaspoons salt and 1 teaspoon pepper until smooth. Pour over the pasta and mix well to bind the ingredients. Stir in the dill, 4 teaspoons salt and 1 teaspoon pepper. Cover with plastic wrap and chill for up to 6 hours to allow the flavors to develop. Check the seasonings and serve chilled or at room temperature.