You could first import your json data in a Python dictionnary :
data = json.loads(elevations)
Then modify data on the fly :
for result in data['results']:
result[u'lat']=result[u'location'][u'lat']
result[u'lng']=result[u'location'][u'lng']
del result[u'location']
Rebuild json string :
elevations = json.dumps(data)
Finally :
pd.read_json(elevations)
You can, also, probably avoid to dump data back to a string, I assume Panda can directly create a DataFrame from a dictionnary (I haven't used it since a long time :p)