One of the most inconsistent things in English is the form of words: one word, two words, or hyphenated? And these forms change rather quickly sometimes; for example, most of our technology words have settled into the one-word, no-cap form — website, email, et cetera — from whatever they were at the beginning.
(And, by the way, the One Word, Two Words, Hyphenated book was compiled and published in 1998 and has not been revised. It is HOPELESSLY out of date.)
There are two sources that are good to use to find out the forms of these words — aside from simply googling the word and seeing how it comes up.
onelook.com: This is a dictionary website. Type in your word as one word, then hyphenated, then two words. See what you find. Caution: You do need to pay attention to which dictionaries are listing forms and look to the reliability of that dictionary. You certainly want to give more weight to the more established dictionaries in making your decision. Sometimes the preferred form is overwhelming — swap meet over swapmeet — and sometimes it is a toss-up — child care versus childcare. When it is a toss-up, you probably want to rely on the form given in the standard dictionary/ies that you normally use: Merriam-Webster, American Heritage.
news.google.com: This source gives you articles to look through. When you are in the site, type in the word you are researching, and news articles will come up that use the word. This gives you the chance to see the form of the word in contemporary news.
If you have a favorite research site, by all means, let me know, and I will get the word out.