Poor Elmo lived with a couple who committed murder, suicide.  When the police came to investigate, he was protecting his home so they tased him.  As a result, he is afraid of strangers, bigger dogs, and small active children. 
He is a very affectionate lap dog at home.  He loves to sit on your lap and give kisses.  Elmo is housetrained and is excited about his walks.
He gets along with the dogs and cats in his foster home.  He wanted to chase the cats when he first arrived, but quickly learned that that was not acceptable and now ignores them.