H1 grace period

[Indirakari]

Hello Friends. 

I was laid off on December 27th, 2017 from my employer A. 
60-day grace period will end on February 28th, 2018.
I found new employer B but they can file only after Feb 28th because of delay in LCA process
I am planning to file for H4 based on my husband H1B so that I will stay on legal status
If H1B is filed after Feb 28th , can I start working with H1B Receipt notice as my old H1B was approved until January 2019(I-797A has approval till 2019)

Any guidance is greatly appreciated. 

Thank You.