Shortly after his birth, his father died and his mother went into business with the violinist Nicolas Mori, a pupil of Viotti by whom she had 5 children, although they weren't married until 1826 (in St. Paul's, Covent Garden).
Lavenu studied at the Royal Academy of Music, firstly with the French harpist Nicolas-Charles Bochsa, and subsequently with Charles Lucas, George Alexander Macfarren, and Cipriani Potter in composition, cello and piano.
In November, 1846 Lavenu's first major work Loretta; A Tale of Seville, a grand opera in three parts with libretto by Alfred Bunn premiered at Drury Lane Theatre before a crowded audience.
[1] After falling into insolvency in 1848, Lavenu became the conductor of the Irish singer Catherine Hayes, making appearances in Great Britain, the United States (1851–52) and Australia (1855).
Lavenu had eight children with Julia, daughter of Colonel John Blossett, the head of the British expedition which aided Simón Bolívar in the wars of independence.