In Croatian and Dalmatian Coats of Arms, by Adam Eterovich, there are several variants fo arms for LUCOVICH/LUKOVICH. This name is most likely of Croatian/Dalmatian Coats of Arms, thus they "had a chateau somewhere in Yugoslavia." However "Yugoslavia" was not declared until 1929. You can find Eterovich's lnks on my link list.
The surname LUCOVICH/LUCOVIC is found almost exclusively in the Istria Peninsula area of Croatia. However there is an old Croatian family surname LUKOVIC (sounds like lookoveech). Antun Lukovic, descendant of an old Croatian family from Boka Kotorska (now this area is mostly in Montenegro), was the chief engineer in the project of building the Suez Canal (1859-1869).
The surnames LUCOVIC and LUKOVIC may be from the same origin. During Venetian/Italian rule many Croatian names and words in the Dalmatian region were changed to suit the Italian langauge. This may be the case in the first letter C in the surname. In Italian that C may have the sound of hard K. However in Croatian this is never the case plain C has the sound of ts as in cats, thus when the area reverted back to Croatian rule some, but not all, surnames went to using K again. Again this MAY be the case.
Here is a timeline for Croatia which may give you some idea of change of rule in Croatia.
Just a bit of historical info to help you. Croatia has existed under several ruling powers over the centuries. Hope this will help:
1) 7th century AD, Croatians arrive in area of present day Croatia and Bosnia
2) 925 AD Small Croatian states unified under King Tomislav
3) 1102 AD Last Croatian King dies, Croatian nobility votes to form personal union with Hungary, where Croaita is an autonomous unit
4) 1527 AD Croatia becomes part of Hapsburg Empire
5) 1857 AD Croatia becomes part of Austro-Hungarian Empire
6) 1918 AD Croatia becomes part of state created by Allied vicotors at the end of WW I when A-H Empire is defeated. New state is called Kingdom of Serbs, Croats and Slovenes and King of Serbia becomes king of new state
7) 1929 AD popular Croatian leader, Stipe Radic, is assassinated by Serbian parliamentarian. King declares royal dicatorship, which many compare to Mussolini and Hitler
8) 1991 AD Croatia voters vote to secede from communist Yugoslavia and becomes independent Repbulichttp://www.croatia-in-english.com/rj/index.html
Croatian Heritage Museum