Am searching. So far I have found no solid documentation of any daughters. Even the Dictionary of National Biography states: " Roger de Lacy married Maude de Clere, sister of the treasurer of York Cathedral, and left by her two sons, John, Earl of Lincoln, and Roger. No reference to any daughters. Maude was not of the "de Clare" family.
I'm afraid that also, not only may some of the information not be correct, but if you follow from this profile down, Eustace fitzJohn, Lord of Alnwick, Constable of Cheshire there are multiple parents as well. Someone needs to check the merges and fix this lineage. They are my grandparents as well.
There is a tradition that a Geoffrey(?) de Whalley married a daughter of Roger de Lacy - said by some to be named Maud. The source, however, appears to be a piece of early 19th century historical fiction about the lords of Clitheroe Castle.
Medlands, incidentally, puts overly much faith in a "manuscript history of the Lacy family" which is manifestly late in composition (15th century or thereabouts) and full of errors (like naming Roger's wife a de Clare instead of a de Clere, and like marrying his mother to her first cousin - which would have required a Papal dispensation which is nowhere recorded).