Remember this graphical illistration?
So has the curve been flattened?
There has been a flattening but, it indicates that the peak was on April the 8th, meaning that the rate of infection peaked about 3 weeks before that on 18th March, which was before Lockdown.
The death rate shows similar.
I hypothesise that if lockdown has had any significant effect on the spread of this virus, then due to the easing of restrictions, there should be a plateauing of data within the next couple of weeks.
The worst case scenario would be a spike, but data from other countries indicates that is not likely to happen.