I personally wouldnt be comfortable leaving a dog outside permanently regardless of age, although I do understand that some people do this with their dogs and having known no different they are apparently quite happy.
In my honest opinion I wouldn't and couldn't leave a 10 week old puppy outside - the weather can be so unpredictable at times particularly at this time of year. Im sure you've seen the footage on the news of the tornado in London, although extreme it certainly came out of the blue and no-one could have prepared for that - imagine if a 10 week old puppy was caught up in that?! Furthermore leaving them outside depending on the security of your property can leave them susceptible to dog theives... some people will do anything these days to get their hands on a pedigree puppy.....