A 40-year-old Plaistow, N.H., man was arrested yesterday in connection with an explosion at a Westville Road condominium complex last Nov. 10.  Derek John Blanchette was arrested and charged with alleged reckless conduct, use of a deadly weapon; endangering the welfare of a child; falsifying physical evidence; acts prohibited, involving ketamine; and acts prohibited, involving methylenedioxymethamphetamine.     Read the article…………………………….