Microphone not detected by Audacity

Hello smart techy people,
I’m having trouble getting Audacity to work with my new external microphone.
The mic’s 3.5 jack is connected to a V-cable / headphone jack splitter that was provided with the mic. (In the other leg of the V-cable I have connected the speakers, which work fine.)
The mic is detected in the Mac’s System Preferences/Sound, and I can see the input level bar responding when speaking into the mic. I have slided the input volume bar to maximum.
Yet in Audacity the external mic does not show up (in Preferences>Devices). Quitting and restarting Audacity does not work, and neither does Transport> Rescan Audio Devices.
I’ve tried changing some settings in Preferences>Quality (but to be honest I have no clue what to select there.)
I think I must have read every available information on this forum and the wider web that combines the words 'Audacity", ‘microphone’ and ‘Mac’, but have run out of ideas. :confused: I’m really hoping one of you has another suggestion! At any rate, thanks for taking the time to read this.

Tech details:
Microphone: Trust Madell 21672 :frowning: https://www.trust.com/en/product/21672-madell-desk-microphone-for-pc-and-laptop#FAQ
Macbook Pro with macOS High Sierra version 10.13.6
Audacity version 2.3.2