Thank you for providing so much detail with the startup issue you are experiencing. I found a couple of resources that may help with the issue you are experiencing.
First, I recommend verifying Macintosh HD OS X, 10.7.5 is selected as the Startup Disk in System Preferences:
Change your startup disk for every startup
- Choose Apple menu > System Preferences, and then click Startup Disk.
- If necessary, click the lock icon and type the name and password for an administrator user.
- Click the icon of the disk you want to use, and then click Restart.
You can find the full article here:
If the issue persists after verifying this setting, I recommend resetting the NVRAM/PRAM on your computer:
Resetting NVRAM / PRAM
- Shut down your Mac.
- Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
- Turn on the computer.
- Press and hold the Command-Option-P-R keys before the gray screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
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