Lorenzo was chosen from among five finalized by a jury made up of established musicians who have had long-running pop careers, the news service reported Sunday.
The jury included Monica Naranjo, Merche and David Bustamante.
The jury's selection coincided with televised viewers' votes, though initially the judges were leaning toward selecting La Brequette.
Lorenzo will sing "Dancing in the Rain" in English at the contest, which is scheduled to be held in May in Denmark.
She came in fourth in Britain's version of "The X-Factor."