Capitalization

Q. What is the proper pronoun form to use to refer to God? I was taught to capitalize the pronoun “He” when “God” was the antecedent. However, I checked a number of standard grammar handbooks and can’t find any information on this point. Have the rules changed?

Q. CMOS mentions that titles are commonly lowercase (president of the United States) but that there is an exception with the title of Speaker. There is debate in my office over the titles of archivist of the United States, Smithsonian secretary, and librarian of Congress. If they do not precede a name, do they remain lowercase?

Q. Besides italicization, does “ceteris paribus” require an initial C? In an article of mine, I wrote: “With this notation, the ceteris paribus cost relevant to the source . . .” The copyeditor capitalized “ceteris” but not “paribus.” Why would that be?