Parents of Diego de Lomelín (ca. 1668, husband of Gerónima de Liebana y Velasco)

The line I am researching is heavily documented down to Diego de Lomelín and his wife, Gerónima de Liebana y Velasco, by many baptisms of their (at least) eight children between 1692 and 1715, and by the baptism of Gerónima (wife of Diego) in 1675. So while the names of the parents of Gerónima are known with certainty (Juan Basilio de Velasco and Nicolasa de Liebana), those of the parents of Diego de Lomelín are not.

Does anyone have proof of the parentage of Diego de Lomelín? All of his children except the last (in 1715) were baptised in Ayo el Chico.

Best wishes,
Lawrence Bouett