In order to help you find the great-grandfather who was “associated with” the Louis Lunch family in New Haven, you need to give at least SOME information about the great-grandfather - particularly his name - and if possible approximate date of birth, names of his wife and children and their DOBs, where the family lived, etc. The Lunch family must have had many people with whom they were associated in some way. Perhaps you might also clarify what you meant by “associated with.” Did you mean related to?
Louis/Lauritz/Laurits/Lawrence can be Scandinavian/American versions of the same name. Is this Lawrence Lunch family the family you meant?
1910 New Haven, New Haven, Connecticut Lawrence Lynch 43 [an Ancestry user correction to Lawrence Lunch] Bridget 38 John 12 Thomas 9 Lovella 7 Lawrence 5 Margaret 3 Edward Lynch 36