Possibly!!
Mine was a loose terminal not screwed back down properly after a garage had been working on my car.
Dont know the underbonnet layout on yours tho so couldnt really advise, on 16v/Willy the battery is located right next to the part it was arcing to when I turned the key.
Even made a nice bright spark to highlight the problem!!
Could always get someone else to turn the key whilst you check it out, might get lucky and its something obvious
Otherwise a new starter motor is in order probably!!!!!!!