There are ways to excite your thinking and generate thoughts through the use of “topoi.” That was the very purpose for which classical rhetorical theorists discussed the concept of “topoi.” “Topoi” were “mental places” to which one could go to help a speaker make and/or develop their point(s).
Likewise, the “Topos of WHEN” is a place to mentally go to help generate content that may help a speaker or preacher develop, drive home, or apply their point(s).
I have already addressed the classical concept of “topoi.” Below is an informative example of the use of “The Topos Of “WHEN.”
√ The sermonic theme was spiritual drifting or being anchored in Christ.
√ These are some of the remarks which set up that theme.
- “If you’re not anchored, you’re going to drift.”
- “We don’t need to just drop anchor; you need to set anchor. If not, you will drift.”
- “A weak link in the chain disconnects the chain, and what use is an anchor that is not connected to the boat.”
√ The speaker exemplifies this topos in developing the application of the main idea.  While any topos can be used to develop any portion of a speech or message (Introduction / Body / Conclusion / Clarification / Application / BigIdea, illustration, etc.), in this case, it is deployed in the application portion of the sermon. The speaker calls up what is believed to be proofs or “textbook signs” of drifting.
√ The rhetorical model, the “topos phrase” which can be used to generate thoughts is . . . .
“You are _________ when . . . . . .”
i.e. You are drifting when . . . .”
√ Here is how it appears explicitly in the sermon.
NOTE: The following 8 examples below do not follow each other, but are distributed throughout the message as applicational points concerning drifting. I have picked them out of the message and listed them together to highlight their use.
“What are some signs of drifting. That we have drifted.”
“You’re drifting when a blue check is more important than a heart check.”
“You’re drifting when my will is more important than God’s will.”
“You’re drifting when you are more worried about everyone else’s business than God’s business.”
“You’re drifting when you’re conformed to the world and not being transformed by God.”
“You’re drifting when our thoughts supersede God’s thoughts.”
(Implied: You are drifting when you are) “No longer participating, but spectating.”
(Implied) “We start resting — and stop striving.”
(Implied) “The only thing you have to do to drift is nothing.” 
Add “WHEN” to your mental toolbox when working on your sermon, when developing a point, or as is the case here, going to application.
1. Source — Christine Caine — Christine Caine and her husband Nick are best known for founding The A21 Campaign in 2008, a 501(c)(3) non-profit, non-governmental organization that combats human trafficking.
2. Whether or not a speaker or preacher knows and understands that a particular rhetorical method is being used, or is consciously engaged in using this-or-that method, does not mean that it is not cognitively happening. It is just an unconscious use of a mental process. i.e. — Intentionality is not required in order to make an “ad hominem” argument.