The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Arbor is a noun. It’s another word for forest.
Ardor is a noun. It means love or affection felt by someone for something or someone else.
The following story uses both words correctly:
In US popular culture, the term “treehugger” was coined to poke fun at environmentalists. While the mental image is a person with great ardor for their local arbor, many environmentalists want to conserve and protect wildlife, waterways, and air quality. It’s not just the trees.