No wireless connecton available on raspberry pi

After a download of NextCloudPi_RaspberryPi_v1.50.2.zip , I imaged it onto a RPI3.
It turns out that network connection is only available through ETH but need to have the device configured with the internal wireless connection.

ifconfig only shows eth0 and lo where as I would have expected wlan0
Also raspi-config tells me there is no wireless interface found

Does any has a clue how to enable the wireless connection?
Is this expected behavior of this image?

Thank you all, Yann