Thanks. Interesting that there's no free alternative for eg. LibreOffice. I guess it's harder than it looks.
http://www.translatortools.net/produ...ools/unbreaker
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Edit: Opening the PDF in Abbyy FineReader does a pretty good job. Gone are the mid-sentence linebreaks (on a few test pages, at least).
An AutoIT script might come in useful to automate the process.