As I recall, the 'tz' sound is only for a double z (like in pizza). I don't think it applies to a single 'z', so
Letizia would be le-TI-zi-a and
Patricia would be pa-TRI-zi-a.
♦ Chrisell ♦
All we have to decide is what to do with the time that is given us. - J.R.R. Tolkien.