Warning: snark factor of seven

I despair of trying to teach good writing skills to my students. If this example, from a reprint of Philippa Gregory's THE OTHER BOLEYN GIRL, is now acceptable to both editors, copyeditors, and readers, I've gone wrong somewhere:

"The lances were down like arrows flying to a target, the pennants on the end of each lance fluttering as the gap closed between them, then the king took a glancing blow which he caught on his shield, but his thrust at Suffolk slid under the shield and thudded into the breastplate."

This, my dears, is a run-on sentence. Times two. It should properly read:

"The lances were down like arrows flying to a target, the pennants on the end of each lance fluttering. The gap closed between them. The king took a glancing blow on his shield, but his thrust at Suffolk slid under the shield and thudded into the breastplate."

One of these can sneak by an author, an editor, and a copyeditor, but this is a whole book full of such offenses. I was prone, being an author myself, to blame the copyeditors and simply think Ms. Gregory doesn't read her galleys, but in a brief visit to her blog, I found that this is characteristic writing for her.

I want to say, despite this, that it's a good story, and the writing is colorful and usually strong. I'm reading on, and simply trying to ignore the run-on sentences. Lord, I hope this experience doesn't blunt my sensibilities so much that I don't know one when I see one! I'm worried that now that the book has been anointed by Hollywood (turned into a movie) that critical faculties across the known world will deteriorate into mush.

And those of you who are my students, don't read the book. Bad example to follow.