Lanzar (Spanish for “to throw, launch”) comes from the Latin lanceare “to pierce with a lance.”
From this root, we can see connections to various English words, including: launch (which is a form of throwing!), lance (it is the stick that the wield to pierce!), and even élan (think of ex-lanceare: to take the energy out of the throw!).
We can see the clear l‑n-z to l‑n-c (or l‑n-ch, in the case of launch) mapping. The ‑z- and ‑c- sounds are similar and thus often swap.