Clue: Victorian author's forename on only novel about abstainer (6)
Answer: LYTTON
Explanation: Definition: Victorian author's forename
*(only) "about" TT (teetotal = "abstainer") 
Refers to Lytton Strachey, who, although born during Victoria's reign, was active after her death. However, he did write a biography of the Queen, so that makes the clue quite clever.