When, if ever, have you seen that particular construction? “I am on every Wednesday…”?
Adverb phrases that express time go either at the beginning or at the end of a sentence.
- Yesterday I went to college
- I went to college yesterday.
The following is very awkward
- I yesterday went to college (NO)
Likewise, the time expression "every Wednesday", is no different
- Every Wednesday I am at college
- I go to college every Wednesday.
The preposition on is used before days of the week, before specific parts of the day and for dates.
- On Wednesdays, I go to college
- The graduation ceremony is on May 14th, and the commencement speech by Tom Smith will begin on Friday morning at 10.30.
There is, however, one usage of “on every + [day]” that sounds idiomatic. When we mention the days and times of TV or radio shows. For example,
It's on every Monday night 7-9pm on BBC Radio Stoke and on the BBC iPlayer.
When To Listen: NOW! It’s on every Monday through Friday at 11AM (and again at 9:30PM) during our Best Selling Fiction program and read by first-time book reader, Geoff Worden.
Spotlight is the show on National Prison Radio which shines a light on those charities and organisations in prison which are there to help you. It’s on every Monday at 11am, repeated at 5pm.
I think afternoon programmes are as good as evening ones and, like I'm out tonight and I know Dallas is on because it's on every Wednesday, so I shall ask him ...
Here, the preposition "on" refers to being broadcast by (a radio or television channel) e.g. ‘a new twelve-part TV series on Channel 4’, ‘The show will be broadcast on CBS on December 26th.’