I’m not an Excel user either, but I do have access to a computer with Excel installed. Here is a picture of a test I did using option-return for in cell line breaks.
Excel has more than one CSV format.
I couldn’t see any difference between Windows and MS-DOS. Both the UTF-8 and Windows formats used a simple carriage return for in cell line breaks. UTF-8 also used a carriage return for line breaks between rows, but Windows and MS-DOS used crlf between rows. UTF-8 also has a UTF-8 byte order mark at the beginning of the file.
Here is a hex dump of the UTF-8 file.
