With scissors, remove underside membrane of lobster tails.
Pull out meat in one piece; dice.
Heat butter in saucepan; saute onion.
Add lobster pieces; stir until meat has lost its translucency and is opaque.
Stir in flour.
Stir in creamed and kernel corn, milk, and mustard; stir over low heat until mixture thickens and bubbles.
Season with salt and pepper.