if statement in LINQ?

Question

i have a couple of list but sometimes they are empty 

var matching = from name in indexnames
                           from surname in indexsurname
                           from age in agesurname
                           from height in indexheight
                           where name.Equals(surname) &&
                                                 name.Equals(age) && name.Equals(height)
                          orderby name
                          select name;

How can i make sure it only does name.Equals(value) if it actualy contains anything ?