Hi, One More Thing:
There are multiple "breakouts" for the small HM-10 module out there. Some have an active chip to do signal level translation for Arduino; some have resistors, some, apparently have none. Check Amazon and you'll see a cluster about $3-4 and another cluster about $8 +
The ones with the active chip look like this:
Look closely on the left near the TXD pin for a tiny 6-pin SMD chip .