From now on. Assuming I clicked all the right buttons, I mean.
Q: Why would you want to see my blog posts on Google+?
A: Four letters: xkcd.
If it works, thank this page.
[Added] It may require switching to the new Blogger interface to make this happen. This may only be a temporary requirement: I did have to switch to make this post appear on my G+ page, because the particular Setting referred to in the page linked to above does not appear under Settings in the old interface. I will have to wait until I put up another post to see if the setting change I made under the new interface persists, even though I have switched back to the old interface.
[Added2] It does appear that you have to be using the new Blogger interface is you want the Google+ posting to happen as described above; i.e., the pop-up prompt did not appear, nor did the auto-posting happen when I switched back to the old interface and put up a new post. If you really hate the new interface and want your Blogger blog posts to appear on G+, you can do this by hand: switch to the new interface, click "Share" under the post(s) you want to share, switch back to the old interface. Tedious, I grant.