Lovro Radonjić is a Croat water polo player and butterfly swimmer who competed for Yugoslavia in the 1952, 1956, and 1960 Summer Olympics. He was born in Korčula, Kingdom of Serbs, Croats and Slovenes. Radonjić was part of the Yugoslav team which won the silver medal in the 1952 tournament. He played all nine matches. Four years later he won again the silver medal with the Yugoslav team in the 1956 tournament. He played six matches. In 1960 he participated in the 200 metre butterfly competition but was eliminated in the first round.
To correct my previous comment: while a default version today, Lovro was actually derived from "Lovrenac", the former Croatian cognate of Laurentius. It's very similar to Slovene Lovrenc but today Lovrenac is very rare and generally unknown.