Hi there,
My surname just so happens to be Jelich however I have had limited success in tracing my family tree down this path more than 3 generations as the trail leads back to Croatia and the records are a nightmare.
Trying to research this family name is fairly difficult as the part of the world my grandfather hails from (Zadar, Croatia) was ruled by Austria, then Italy, then Yugoslavia and is now Croatia.
The matter is further compounded by the fact that the surname Yelich is the phonetic spelling of the slavic surname Jelić which I have been informed (whether correctly or not is another question) is originally from the Montenegro part of the world and is apparently a fairly common name.
One source (a Serbian man) informed me that the name meaning is after a type of pine tree with a similar name.
However in my case I have found many different spelling variations of the same name Jelic, Jelich, ielic, iellich, ielich and yelich. The reason for the use of the I is that if your ancestor had any documents issued by Italian authorities, they don't have a J in their alphabet. When this name is anglicised the I may have been converted to a J or a Y.
I don't know whether any of this may help you or not but good luck with your search.