Prepare the lobster: Cook the lobsters in boiling salted water for 3 to 4 minutes, or until slightly underdone. Remove from the water and let cool slightly. Remove the lobster meat from the shells, reserving the meat and the shells. Coarsely chop the lobster meat.
Prepare the corn: Remove husks from the corn and cut kernels off the cobs. Reserve the corn, cobs, and half of the husks.
Make the bisque: Place the lobster shells, corn cobs, husks, bay leaves, thyme sprigs, and peppercorns in a stockpot and add enough water to barely cover. Simmer for 45 minutes, then strain through a fine mesh sieve, discarding the solids. Place the broth in a large saucepan and simmer over medium heat for 45 minutes, or until reduced to 1 1/2 quarts. Season to taste with salt and pepper.
In a small saucepan, place half of the corn kernels and the heavy cream. Cook over medium heat for 10 minutes, or until the cream is reduced to about 1 cup. Remove from the heat and puree until smooth. Season to taste with salt and pepper.
Cook the bacon over medium-low heat for 10 minutes, or until the fat is rendered but not brown. Remove the bacon from the pan and discard. Saute the remaining corn, the potatoes, and onion in the bacon fat over medium heat for 10 minutes, or until the potatoes are tender. Drain any fat from the pan, add the pureed corn mixture, and cook over medium heat for 5 minutes, or until thick. Add the lobster stock in small additions until the desired consistency is reached. Add the lobster meat to the pan and whisk in the butter just prior to serving.
Ladle the soup into 10 bowls and sprinkle with the chervil leaves. Top with freshly ground black pepper to taste.
Preheat the oven to 400 degrees.
Slice each piece of bread on the diagonal into triangular pieces. To shape each crouton, slice off the crust on one side of the triangle, then make a parallel slice, removing a corner of the bread. Trim the remaining crust with three small cuts to make a wedge.
Spread the butter with your fingers in the center of a cookie sheet. Press each wedge into the butter and rub gently to coat on one side, then turn it over, buttered side up. Arrange all the wedges on the buttered area of the sheet and place in the oven. Toast the croutons for 8 to 10 minutes, until nicely colored and crisp.
To serve, pile the fresh parsley in a small mound. Dip the point of the toasted wedge into the beef-stew sauce, then press the moistened end into the parsley to coat. Arrange 2 croutons on every serving plate or bowl of stew.