As written, the conclusion doesn't follow. It holds once one premise is added.
Nothing else was changed.
Source
Raising the minimum wage forces small businesses to cut staff, and this city just raised its minimum wage. So local shops will soon be laying people off.
- #
Raising the minimum wage forces small businesses to cut staff.
- #
This city just raised its minimum wage.
- added#
If raising the minimum wage forces small businesses to cut staff and this city just raised its minimum wage, then local shops will soon be laying people off.
Bridges the premises to the conclusion.
- #
Therefore, local shops will soon be laying people off. [1,2,3]
As written, before the added premise
Raising the minimum wage forces small businesses to cut staff.
This city just raised its minimum wage.
Therefore, Local shops will soon be laying people off. [1,2]
What's missing
The conclusion introduces 'Local shops' (a subset of 'small businesses') and 'soon' (a temporal qualifier) not present in the cited premises. Additionally, premise 1 uses 'forces...to cut staff' while the conclusion says 'laying people off' — a reworded concept. These are unstated bridge premises needed to connect the general claim about small businesses to local shops specifically, and to add the temporal dimension. A bridge premise could fix this, so the argument is opaquely valid rather than invalid.