original page

I see this advice mentioned in quite a few places. However, the over/under distinction is often unclear. BOTH ways have the string going over the loop.

In the page above, the confusion is made far worse by the fact that the diagram fails to indicate which is the standing end and which is the working end — ie. which direction the string is being secured.

clarification

First, the stitch is properly called the "running lock-stitch", or sometimes "running stitch"; the term "lock stitch" by itself seems to be ambiguous? It doesn't seem to be the same as this lockstitch.

Second, it clarifies the over/under thing greatly:

One thing must be kept in mind when making running stitches: The twine must always be run over and then under the loop before it, and not under and then over. This way, the twine is secured beneath the loop.