Discuss how Elrond advances the plot of this story?

Much like Gandalf Elrond serves as a mentor type figure. He doesn't so up much in the Hobbit. He is able to decipher the Lonely Mountain map and Rivendell certainly provides a place of refuge for Bilbo both at the beginning and end of the story. Elrond is wise and has a spirituality that connects him with the natural elements unlike any other species in Tolkien's universe. Elrond becomes more prominent in the next book.