Q. Can you inform me how you would recommend writing out “10:05 a.m.” if an author is very set on using words rather than numerals?

A. Certainly. You can write “five past ten in the morning,” for instance. There are various ways to write times of day. Please see CMOS 9.37 (“Numerals versus Words for Time of Day”) for more suggestions. Please note that it’s conventional to use numerals for odd times like 10:05, however. Spelling out is usually reserved for the hour, half hour, and quarter hour.